Finding what is common to two arrays

Question

Is there a way to compare two arrays and show what is common to both of them?

array1 = [\"pig\", \"dog\", \"cat\"]
array2 = [\"dog\", \"cat\", \"pig\", \"hor         


        

Answer 1

You can intersect the arrays using &:

array1 & array2

This will return ["pig", "dog", "cat"].

Answer 2

Set Intersection. Returns a new array containing elements common to the two arrays, with no duplicates, like:

["pig", "dog", "bird"] & ["dog", "cat", "pig", "horse", "horse"]
# => ["pig", "dog"]

You can also read a blog post about Array coherences